U.S. patent application number 16/629126 was filed with the patent office on 2020-04-30 for main body of a doctor blade chamber, doctor blade chamber thereof and methods of manufacturing same.
This patent application is currently assigned to BOBST LYON. The applicant listed for this patent is BOBST LYON EPSILON COMPOSITE. Invention is credited to Rene BAZIN, Philippe FLEURY, Julien MATTRAND, Steve Peter Daniel WILLEMS.
Application Number | 20200130348 16/629126 |
Document ID | / |
Family ID | 60182712 |
Filed Date | 2020-04-30 |
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United States Patent
Application |
20200130348 |
Kind Code |
A1 |
BAZIN; Rene ; et
al. |
April 30, 2020 |
MAIN BODY OF A DOCTOR BLADE CHAMBER, DOCTOR BLADE CHAMBER THEREOF
AND METHODS OF MANUFACTURING SAME
Abstract
A main body of doctor blade chambers including a first portion
configured to hold a first doctor blade, a second portion
configured to hold a second doctor blade, a third portion
connecting the first portion and the second portion, a cavity
intended to receive ink and defined at least by the first portion,
the second portion and the third portion, characterized in that the
main body is a single closed hollow profile extending along a
longitudinal main axis X-X, the main body being made of pultruded
composite material.
Inventors: |
BAZIN; Rene; (Farnay,
FR) ; FLEURY; Philippe; (Saint Jean des Vignes,
FR) ; MATTRAND; Julien; (Decines-Charpieu, FR)
; WILLEMS; Steve Peter Daniel; (Hourtin, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOBST LYON
EPSILON COMPOSITE |
Villeurbanne
Gaillan |
|
FR
FR |
|
|
Assignee: |
BOBST LYON
Villeurbanne
FR
EPSILON COMPOSITE
Gaillan
FR
|
Family ID: |
60182712 |
Appl. No.: |
16/629126 |
Filed: |
July 6, 2018 |
PCT Filed: |
July 6, 2018 |
PCT NO: |
PCT/FR2018/051702 |
371 Date: |
January 7, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 70/52 20130101;
B41F 31/027 20130101; B29L 2031/767 20130101 |
International
Class: |
B41F 31/02 20060101
B41F031/02; B29C 70/52 20060101 B29C070/52 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 7, 2017 |
FR |
17/56404 |
Jul 28, 2017 |
FR |
17/57253 |
Claims
1. A main body of a doctor blade chamber comprising a first portion
configured to hold a first doctor blade, a second portion
configured to hold a second doctor blade, a third portion
connecting the first portion and the second portion, a cavity
intended to receive ink and delimited at least by the first
portion, the second portion and the third portion, wherein the main
body is a single hollow closed profile extending according to a
longitudinal main axis X-X, the main body being made of a pultruded
composite material.
2. The main body according to claim 1, wherein the composite
material is a pultruded composite carbon.
3. The main body according to claim 1, wherein the composite
material in which the main body is formed comprises a fiber volume
strictly larger than 60% of the volume of the composite.
4. The main body according to claim 3, wherein the fiber volume is
between 61% and 70% of the volume of the composite.
5. The main body according to claim 1, comprising a non-woven
fabric arranged on the surface of the main body, the non-woven
fabric being integrated into the mass of the main body.
6. The main body according to claim 1, wherein the composite
material in which the main body is made by pultrusion with a fiber
rate strictly higher than 60%, has a performance ratio higher than
112% compared to the performance ratio of the same composite
material in low-pressure resin injection molding.
7. A doctor blade chamber comprising: a main body according to
claim 1, a first doctor blade mounted on a first portion of the
main body, a second doctor blade mounted on a second portion of the
main body, opposite the first doctor blade.
8. The doctor blade chamber according to claim 7, comprising a
pressurized water channel, arranged in the main body.
9. The doctor blade chamber according to claim 8, wherein the water
channel comprises at least one washing nozzle opening into the
water channel and protruding from the water channel through the
third portion of the main body.
10. The doctor blade chamber according to claim 8, wherein the
water channel is positioned in a hollow of the profile of the main
body, a first side of the water channel being arranged against a
first internal face of the main body and a second side of the water
channel, opposite to the first side of the water channel being
arranged against a second internal face of the main body.
11. The doctor blade chamber according to claim 8, wherein the
water channel is a profile made of a composite material comprising
carbon.
12. A method for manufacturing a main body of a doctor blade
chamber, the manufacturing method comprising at least one step of
pultruding a main body according to claim 1.
13. A method for manufacturing a doctor blade chamber according to
claim 7, the manufacturing method comprising at least one step of
obtaining a main body according to the manufacturing method
comprising at least one step of pultruding a main body of a doctor
blade chamber comprising a first portion configured to hold a first
doctor blade, a second portion configured to hold a second doctor
blade, a third portion connecting the first portion and the second
portion, a cavity intended to receive ink and delimited at least by
the first portion, the second portion and the third portion,
wherein the main body is a single hollow closed profile extending
according to a longitudinal main axis X-X, the main body being made
of a pultruded composite material.
14. The manufacturing method according to claim 13, comprising at
least one additional step of inserting and assembling a water
channel shaped to form a water network in the main body of the
doctor blade chamber.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention concerns the technical field of doctor
blade chambers for flexographic rotary printing units and more
particularly the method for manufacturing such a doctor blade
chamber and the main body of the doctor blade chamber.
[0002] Flexography is a rotary printing process which can be used
on many substrates, for example of the sheet or web type, made of
cardboard or plastic material, and requiring the use of flexible
and relief plates, or printing forms.
[0003] In flexography, a printing unit comprises a plate cylinder,
configured to carry the printing plate, a screened or anilox
roller, having over its surface a plurality of cells intended to
collect ink in an amount controlled by the volume of the cells, the
screened roller being configured to transfer the ink on the plate,
a doctor blade chamber, configured to fill the cells of the
screened roller, a pump, ensuring the ink supply from the ink tank
to the doctor blade chamber, and an back pressure cylinder holding
the media being printed against the plate cylinder.
[0004] In FIG. 1 is schematically illustrated this structure of
printing units. A printing machine comprises several printing units
placed one after the other and each dedicated to a specific
color.
[0005] In the present invention, the term flexography means a
rotary printing method that can be used on many medias and that
requires the use of relatively flexible and relief, plates or
printing forms.
STATE OF THE ART
[0006] Conventionally, a doctor blade chamber is made of metal,
preferably aluminum, for manufacturing reasons, the metals can be
processed by extrusion.
[0007] However, a doctor blade chamber is an element that can reach
several meters long and that is, by its volume and the material
used to make it, heavy and difficult to handle and transport in
particular during maintenance: cleaning, replacement of a part or
other.
[0008] To facilitate the design and to lighten the doctor blade
chamber, the latter is often designed into several parts in
particular the main body as described in the document WO2016192735
A1. Nevertheless, the cost of production increases insofar as the
number of parts increases to make this main body and the handling
of the parts remains difficult, especially since at least one
mounting operation is necessary. Furthermore, the gluing and
assembly elements come to weigh down the assembled part, which
increases the risks related to the collapse and the fatigue of the
assembled junctions. In addition, the additional assembly/gluing
operations reduce productivity in the process of making the doctor
blade chamber. Moreover, these parts are often made by liquid resin
injection molding (RTM), which has the drawbacks of obtaining parts
whose section thickness is variable and whose fibers compaction is
heterogeneous.
OBJECT OF THE INVENTION
[0009] The invention aims at overcoming all or part of the
aforementioned drawbacks.
[0010] An object of the invention is a main body of doctor blade
chambers comprising a first portion configured to hold a first
doctor blade, a second portion configured to hold a second doctor
blade, a third portion connecting the first portion and the second
portion, a cavity intended to receive ink and delimited at least by
the first portion, the second portion and the third portion,
characterized in that the main body is a single hollow closed
profile extending according to a longitudinal main axis X-X, the
main body being made of a pultruded composite material.
[0011] Thanks to the configuration of the main body of the doctor
blade chamber according to the invention, the doctor blade chamber
is lighter, more robust and resistant due to the use of a pultruded
composite material, and the configuration in a single profile
avoids the complex and time-consuming, and therefore expensive,
mounting/assembly operations. Furthermore, the pultrusion allows
obtaining stable mechanical properties and a constant and uniform
thickness in all points of the section and over the entire length
of the profile. In addition, the pultrusion allows having a piece,
in this instance the main body, having a porosity of less than 2%
and preferably less than 1%.
[0012] In the present invention, pultrusion means a method for
continuously manufacturing tubes and profiles made of composite
materials.
[0013] According to an embodiment of the invention, the main body
has a section with a constant thickness. This feature is inherent
to the pultrusion method used to make the main body.
[0014] According to a feature of the invention, the pultruded
composite material comprises thermoplastic fibers and/or aramid
fibers and/or glass fibers and/or high modulus carbon fibers and/or
high-strength carbon fibers. Preferably, the pultruded composite
material is a pultruded composite carbon material.
[0015] According to a feature of the invention, the composite
material in which the main body is made comprises a fiber volume
strictly larger than 60% of the volume of the composite.
Preferably, the volume of fiber is between 61% and 70% of the
volume of the composite.
[0016] Thanks to this composition, the pultruded composite material
has a specific modulus corresponding to a ratio between the
longitudinal modulus of elasticity or Young's modulus of the
composite and the density of the composite, much larger than the
specific modulus of a pre-impregnated molded composite material,
than that of a pultruded composite material comprising 60% or less
of fibers relative to the volume of the composite, and also than
that of a composite material molded by low-pressure injection of
resin.
[0017] Preferably, the pultruded composite material comprises
between 61% and 70% of high-strength carbon fibers relative to the
volume of the composite material.
TABLE-US-00001 TABLE 1 Example of specific modulus results for a
composite material with high-strength carbon fibers according to
its volume of fibers in the material and the used manufacturing
method. fiber volume in the Young's Specific perfor- Used composite
density modulus modulus mance methods (%) (Kg/m.sup.3) (KN/m.sup.2)
KNm/kg ratio * Low-pressure 50 1524 120 000 000 78740 100%
injection molding of resin Molding of 56 1558 130 000 000 83440
106% prepreg Pultrusion .ltoreq.60% 1581 140 000 000 88552 112%
Pultrusion 65 1605 149 000 000 92835 117% Pultrusion .gtoreq.70%
1632 160 000 000 98039 124% * compared to low-pressure injection
molding of resin
TABLE-US-00002 TABLE 2 Example of specific modulus results for
different used materials. fiber volume in the Young's Specific
perfor- Used Used composite density modulus modulus mance materials
Process (%) (Kg/m.sup.3) (KN/m.sup.2) KNm/kg ratio * Composite Low-
50 1524 120 000 000 78740 100% material pressure with high-
injection strength molding carbon of resin fibers Aluminum
extrusion N/A 7850 205 000 000 26115 33% * compared to low-pressure
injection molding of resin of a composite material comprising 50%
of high-strength carbon fibers
[0018] As shown in the example illustrated in Table 1 hereinabove,
the pultruded composite material comprising more than 60% of
fibers, has a much greater specific modulus than the specific
modulus of a pre-impregnated molded composite material, than that
of a pultruded composite material comprising 60% or less of fibers
relative to the volume of the composite, and also than that of a
composite material molded by low-pressure injection of resin.
[0019] According to a feature of the invention, the composite
material in which the main body is made by pultrusion with a fiber
rate strictly larger than 60%, has a performance ratio higher than
112% compared to the performance ratio of the same composite
material in low-pressure injection molding of resin.
[0020] According to a feature of the invention, the main body
comprises a non-woven fabric integrated in the mass of the main
body and arranged flush with the external surface of the main body.
The integration of a non-woven fabric at the surface of the main
body has the advantage of facilitating the cleaning of the doctor
blade chamber in order to avoid a mixture of an ink with residues
of the color of the previously used ink. Furthermore, the non-woven
fabric allows reducing the surface tension of fluids and developing
the qualities of the profile of the main body in particular in
machining and in delamination.
[0021] Advantageously, the integration of the fabric is carried out
at the same time as the making of the main body of the doctor blade
chamber.
[0022] According to a feature of the invention, the non-woven
fabric is a veil with a thickness comprised between 0.05 mm and 1
mm.
[0023] According to a feature of the invention, the non-woven
fabric at least partially covers a portion of the surface of the
main body. Preferably, the non-woven fabric covers at least the
surface of the first portion and/or the second portion and/or the
third portion of the main body. Even more preferentially, the
non-woven fabric covers the entire surface of the main body.
[0024] According to a feature of the invention, the non-woven
fabric is a fabric comprising at least fibers, for example organic,
inorganic or thermoplastic fibers.
[0025] According to a feature of the invention, the doctor blade
chamber comprises at least one pressurized water channel, arranged
in the main body. The purpose of the water channel is to wash the
doctor blade chamber and remove residual inks.
[0026] According to a feature of the invention, the water channel
extends over at least one portion of the length of the main body,
preferably over the entire length of the main body. The water
channel is housed in the hollow of the main body at the level of
the third portion.
[0027] According to a feature of the invention, the water channel
comprises at least one washing nozzle opening into the cavity of
the main body and protruding from the water channel through the
third portion of the main body.
[0028] Preferably, the water channel comprises a plurality of
washing nozzles. Advantageously, the washing nozzles of the
plurality are evenly spaced all along the water channel.
[0029] According to a feature of the invention, the third portion
is set back with respect to the first portion and to the second
portion of the main body, so that between the first portion and the
second portion a cavity is formed.
[0030] According to a feature of the invention, the washing nozzles
open into the cavity formed by the first, second and third portions
of the main body.
[0031] According to a feature of the invention, the first doctor
blade and the second doctor blade partially close the cavity formed
by the first, second and third portions of the main body. The
purpose of the first doctor blade and the second doctor blade is to
scrap the screened roller intended to come partially in the doctor
blade chamber.
[0032] According to a feature of the invention, the main body
comprises a first face intended to be opposite the screened roller,
and a second face opposite to the first face.
[0033] According to a feature of the invention, the water channel
is positioned in a hollow of the profile of the main body, a first
side of the water channel being arranged against a first internal
face of the main body and a second side of the channel of water,
opposite to the first side of the water channel being arranged
against a second internal face of the main body.
[0034] According to a feature of the invention, the water channel
is glued to the main body. Advantageously, the gluing of the water
channel is made with an expansive glue for sealing. The glue used
to glue the water channel is for example a thermosetting glue.
[0035] According to a feature of the invention, the water channel
is made of a composite material comprising, for example, carbon.
According to a feature of the invention, the water channel is a
profile.
[0036] According to a feature of the invention, the water channel
has a substantially rectangular cross-section.
[0037] According to a feature of the invention, the doctor blade
chamber further comprises an ink channel, extending at least
partially along the main body, preferably all along the main body.
The purpose of the ink channel is to achieve the inking of the
printing unit by flexography.
[0038] Advantageously, the ink channel is arranged in the hollow of
the profile of the main body, and has at least one ink outlet
opening into the ink channel and protruding from the ink channel
through the third portion of the main body.
[0039] According to a feature of the invention, the ink channel is
made of a composite material comprising for example carbon.
According to a feature of the invention, the ink channel is a
profile.
[0040] According to a feature of the invention, the ink channel has
a substantially circular cross-section.
[0041] According to a feature of the invention, the doctor blade
chamber comprises a first end part and a second end part, each end
part being arranged at one end of the main body of the doctor blade
chamber.
[0042] According to a feature of the invention, a portion of the
first end part is inserted into a first end of the profile of the
main body.
[0043] According to a feature of the invention, a portion of the
second end part is inserted into a second end of the profile of the
main body.
[0044] Advantageously, each end part is inserted and then glued
into the main body.
[0045] According to a feature of the invention, the first end part
has at least one orifice shaped so as to house a pipe connecting
the water channel to a water tank.
[0046] According to a feature of the invention, the first end part
has a second orifice shaped so as to house a pipe connecting the
ink channel to an ink tank.
[0047] Another object of the invention is a method for
manufacturing a main body of doctor blade chambers, the
manufacturing method being characterized in that it comprises at
least one step of pultruding a main body according to the
invention.
[0048] Another object of the invention is a method for
manufacturing a doctor blade chamber according to the invention,
the manufacturing method comprising at least one step of obtaining
a main body according to the invention by pultrusion.
[0049] According to a feature of the invention, the manufacturing
method comprises at least one additional step of inserting and
assembling, preferably by gluing, a water channel shaped so as to
form a water network in the main body of the doctor blade
chamber.
[0050] According to a feature of the invention, the water channel
is assembled preferably glued in the cavity of the profile of the
main body and particularly against the first face and the second
face of the profile of the main body.
[0051] Advantageously, the glue used to glue the water channel is
an expandable glue for sealing the assembly.
[0052] According to a feature of the invention, the manufacturing
method comprises a step of drilling at least one orifice in the
main body and in the water channel, the drilling step enabling the
subsequent positioning of washing nozzles.
[0053] According to a feature of the invention, the manufacturing
method further comprises a step of inserting an ink channel within
the doctor blade chamber.
[0054] According to a feature of the invention, the manufacturing
method comprises a step of inserting and assembling, preferably by
gluing, a first end part at one end of the main body of the doctor
blade chamber and a second end part at the other end of the main
body, while connecting the first end part to the water channel and
to the ink channel.
BRIEF DESCRIPTION OF THE FIGURES
[0055] The invention will be better understood, thanks to the
description hereinafter, which relates to an embodiment according
to the present invention, provided as a non-limiting example and
explained with reference to the appended schematic figures, in
which identical reference numerals correspond to structurally
and/or functionally identical or similar elements. The appended
schematic figures are listed hereinbelow:
[0056] FIG. 1 is a schematic illustration of a flexographic
printing unit comprising a conventional doctor blade chamber,
[0057] FIG. 2 is a perspective view of the doctor blade chamber
according to the invention,
[0058] FIG. 3 is a perspective view of the main body of the doctor
blade chamber according to the invention and as illustrated in FIG.
2,
[0059] FIG. 4 is a partial perspective view of the doctor blade
chamber according to the invention and as illustrated in FIGS. 2
and 3,
[0060] FIG. 5 is a detail view according to box A of FIG. 4,
[0061] FIG. 6 is a partial detail view of the doctor blade chamber
according to the invention and as illustrated in FIGS. 2 to 5,
[0062] FIG. 7 is a side view of the main body of the doctor blade
chamber according to the invention.
DETAILED DESCRIPTION OF THE FIGURES
[0063] As described above to illustrate the context of the
invention, a printing unit 100 comprises: [0064] a plate cylinder
104 configured to support a plate or printing form 108, [0065] a
screened or anilox roller 103, having over its surface a plurality
of cells intended to collect ink in an amount controlled by the
volume of the cells, the screened roller 103 being configured to
transfer the ink onto the plate 108, [0066] a doctor blade chamber
101, configured to fill the cells of the screened roller 103,
[0067] a pump 102, ensuring the ink supply from the ink tank 107 to
the doctor blade chamber 101, and [0068] a back pressure cylinder
105 holding the support being printed 106 against the plate
cylinder 104, and thus against the plate 108.
[0069] The doctor blade chamber of the invention is designated by
the reference numeral 1 and is illustrated in detail with reference
to FIGS. 2 to 7.
[0070] The doctor blade chamber 1 according to the invention
comprises a main body 2 made in one-piece which is a closed hollow
profile, as illustrated in particular in FIG. 3. The main body 2
has a constant and uniform thickness in all points of the section
and over the entire length of the profile, as illustrated in
particular in FIGS. 3, 6 and 7. The main body 2 extends according
to a longitudinal main axis X-X as illustrated in particular in
FIGS. 2 and 3. Furthermore, the main body 2 is made of pultruded
composite carbon.
[0071] As shown in FIG. 3, the main body 2 has a first portion 2a,
a second portion 2b and a third portion 2c. The third portion 2c
connects the first portion 2a and the second portion 2b, the third
portion 2c being shaped and intended to partially receive a
screened roller therewithin. As shown in FIG. 3, the third portion
2c is set back with respect to the first portion 2a and to the
second portion 2b of the main body 2, so that between the first
portion and the second portion, a cavity 2e is formed.
[0072] Furthermore, the main body 2 has a first face 2.1 intended
to be opposite the screened roller and a second face 2.2 opposite
to the first face 2.1 as illustrated in FIG. 3.
[0073] According to the invention, the doctor blade chamber 1
further comprises a first doctor blade 3, the first doctor blade 3
being mounted on the first portion 2a of the main body 2 by means
of a first doctor blade flange 5 as represented in FIGS. 2 and 7.
Each flange is held by a fastening system 7 consisting of the
cooperation of a screw or a pin, shown in FIG. 2 with an insert 7a
and shown in FIGS. 4 and 7 for example. In addition, the doctor
blade chamber 1 comprises a second doctor blade 4, the second
doctor blade 4 being mounted on the second portion 2b of the main
body 2, opposite the first doctor blade 3, by means of a second
doctor blade flange 6 as represented in FIGS. 2 and 7. In the
example illustrated in FIGS. 2 and 7, the first doctor blade 3 and
the second doctor blade 4 partly close the cavity 2e formed by the
first 2a, second 2b and third 2c portions of the main body 2.
[0074] According to the invention, the main body 2 comprises a
non-woven fabric 16 arranged on the surface of the main body 2 as
represented in solid line in FIG. 7. In the example illustrated in
FIG. 7, the non-woven fabric 16 is represented as covering the
entire surface of the main body 2 but, in variants which are not
represented, the non-woven fabric could cover only one portion of
the main body 2 for example only the first face 2.1 or only the
second face 2.2 or only one of the portions 2a, 2b, 2c of the main
body 2.
[0075] According to the invention, and as represented in particular
in FIG. 7, the doctor blade chamber 1 comprises a pressurized water
channel 11, arranged in the main body 2 and more specifically in
the hollow 2d of the profile of the main body 2 at the level of the
third portion 2c. The water channel 11 advantageously extends over
the entire length of the main body 2. Advantageously, the water
channel 11 is a profile with a substantially rectangular
cross-section.
[0076] As shown in FIG. 7, a first side 2.3 of the water channel 11
is arranged against the first internal face 2.1 of the main body 2
and a second side 2.4 of the water channel 11, opposite to the
first side of the channel of water 11 is arranged against the
second internal face 2.2 of the main body 2.
[0077] According to the invention, the water channel 11 comprises
at least one plurality of washing nozzles 10 opening into the water
channel 11 and protruding from the water channel 11 through the
third portion 2c of the body main 2 as illustrated in FIGS. 2 and
7. In the example illustrated in FIG. 7, the water channel 11 is
glued in the main body 2 by means of an expansive glue 17 for
sealing. Advantageously, the washing nozzles 10 of the plurality
are evenly spaced all along the water channel 11. As shown in FIG.
7, the washing nozzles 10 open into the cavity 2e formed by the
first, second and third portions 2a, 2b, 2c of the main body 2.
[0078] Moreover, the doctor blade chamber 1 according to the
invention comprises an ink channel 12, extending all along the main
body 2 and arranged in the hollow 2d of the profile of the main
body 2. The ink channel 12 comprises at least one ink outlet 13
illustrated in FIG. 6 opening into the ink channel 12 and
protruding from the ink channel 12 through the third portion 2c of
the main body 2. Advantageously, the ink channel 12 is a profile
with a substantially circular cross-section.
[0079] According to the invention, the doctor blade chamber
comprises a first end part 8a and a second end part 8b, each end
part 8a, 8b being arranged at one end of the main body 2 of the
doctor blade chamber 1. As shown in particular in FIG. 4, a portion
of the first end part 8a is inserted into a first end of the
profile of the main body 2 and a portion of the second end part 8b
is inserted into a second end of the profile of the main body
2.
[0080] Advantageously, the first end part 8a has at least one
orifice shaped so as to house a pipe 9a connecting the water
channel 11 to a water tank and a second orifice shaped so as to
house a pipe 9b connecting the ink channel 12 to an ink tank as
illustrated in FIGS. 7 and 2.
[0081] Moreover, the doctor blade chamber 1 comprises a supporting
element 14 illustrated in FIGS. 2 to 5 and 7 arranged on the second
face 2.2 of the main body 2 and configured to strengthen the doctor
blade chamber 1. In addition, the doctor blade chamber 1 comprises
a hook 15 intended to enable the hooking of the doctor blade
chamber system 1.
[0082] Of course, the invention is not limited to the embodiment
described and represented in the appended figures. Modifications
are still possible, in particular with regards to the constitution
of the various elements or by substitution with technical
equivalents, yet without departing from the scope of the
invention.
* * * * *